A variable, as the name implies, is anything that can change. In other words, it refers to anything that has a quantity or quality that varies. According to Polit and Hungler (1978), a variable is an abstract entity which takes on different values. Age, weight, temperature, colour, score and career choice are all examples of variables.In scientific method of investigation, elucidating a cause-and-effect relationship between objects requires that variables are classified as independent, dependent, or confounding. An independent variable is one that, when manipulated, causes a change in another variable. The variable that changes in response to that manipulation is referred to as a dependent variable. A confounding or extraneous variable is anything other than the independent variable of interest that may affect the dependent variable (Kallet, 2004).